exactly, it means nothing at all... if there is no same grade "alternative" copy with better pq at a reasonable premium to the lessor pq copy, that the ebay buyer had a chance to purchase at the SAME time, there is nothing from which to draw a conclusion... the sale is not relevant or relative to other sales
but, when market conditions exist so that one/buyer can make a purchasing decision between 2 copies, with distinquishable (as defined by cgc) pq, THEN the better pq will garner higher demand and higher price in almost every instance (always exceptions)...